why resin tries to redirect when isCommited in httpresponse is set to true.

Forum,
I wanted to understand something about resin response writing when jsp's are having errors. Lets say we have a expression {resin.forumName} and object resin doesn't have attribute forumName. Resin throws PropertyNotFoundException and com.caucho.jsp.PageContextImpl.handlePageException commits response. Why does resin try to sendRedirect as response is already commited. I see HTTPservletresponse interface defines sendRedirect to throw IllegalStateException if response is already commited.